Large-angle scanning ellipsoid dielectric lens antenna based on phased array feed
Technical field
The invention belongs to antenna technical fields, are related to ellipsoid dielectric lens antenna, are specifically used for beam scanning
With the large-angle scanning ellipsoid dielectric lens antenna based on phased array feed of multi-beam communication, work is particularly suitable in millimeter wave
Frequency range, compared with low section, large-angle scanning and 5G communication etc. usage scenarios.
Background technique
Multibeam antenna has become an important branch in modern antennas, with marine navigation, satellite communication, electronics
The urgent need of the fields to multibeam antenna such as confrontation and target tracking has high-gain, Sidelobe, wide scan angle, sweeps at a high speed
It retouches and multibeam antenna the features such as manufacturing cost is low is paid close attention to.The present invention is based on the demand, devises base
In phased array feed large-angle scanning ellipsoid dielectric lens antenna, be particularly suitable for work in millimeter wave frequency band, compared with low section, width
The usage scenarios such as angle sweep and 5G communication.
Phased array antenna and the primary Lens antenna of dragon are presently the most the multibeam antenna form of mainstream.Wherein dragon uncle is saturating
Mirror antenna can be good at meeting current communication system for antenna multi-beam due to its own symmetry and wideband structural
The requirement of scan characteristic and wide-band application, but simultaneously because lens antenna in multi-beam scanning dependent between different feeds
Switching, although so multi-beam scanning application in have good consistency, required port number is excessive, causes antenna
The difficulty and the disadvantage on dimensional weight of processing.
Traditional phased array antenna is being moved in the excitation amplitude and phase that carry out only changing each unit when multi-beam scanning
The scan characteristic that less number of unit realizes degree of precision can be used in the enough situations of phase device precision, but because of its wide-angle
Scan capability is lacking, and required T/R component count is more, higher cost, it is made generally to be difficult to use in commercial communication neck
Domain, so it not is good scheme that phased array antenna, which is used alone,.
In recent years, with the proposition of transform optics (Transformation Optics) theory, many new type lens antennas
It is devised, is also turned one's attention in the improvement of the primary lens of traditional dragon there are many researcher, the primary lens of dragon are expected to be reborn.
The primary ball of dragon can be compressed by flat-plate lens using transform optics method, not only volume is light and handy, there can also be the focusing of plane
Face is easily integrated, but the primary lens electromagnetic parameter of transformed dragon changes, and often embodies anisotropy, and real material is difficult
To be formed.
Its dielectric constant of theoretic spherical Luneburg lens meets 2 to 1 changing rule from internal layer to surface, therefore always
Since material technology and manufacture level limit the application of this antenna.It is studied by many years, proposes material manufacture craft
Some basic skills and criterion, wherein most representative is heat foamable technology based on plastic resin material, based on drilling
Structure is realized compared with low-k equivalence techniques.SEI Corporation passes through in patent CN 101057370
Die sinking method foams to foamed plastics pearl material, but this method and process process is extremely complex and uniform in foaming is difficult to control
System, requires processing conditions very high, leads to that processing cost is uncontrollable, batch production is difficult.United States Patent (USP) inventor
" the Lens of Gradient entitled disclosed in 6433936 B1 of patent No. US such as Michael.P.Carpenter
In Dielectric Constant and Methods of Production " by thermoplastic resin expand pearl (polystyrene,
Polyamide etc.) in doped ceramics material (titanium dioxide, silica etc.) filling mold in, and heat so that them is molten to one
It rises, controls the dielectric constant of every layer of spherical shell by adjusting density and the ceramic content of foam molded articles, the lens are light-weight, energy
Guarantee preferable practicability, but process flow is relative complex, is not suitable for volume production.Southeast China University Cui Tiejun professor team exists within 2011
It is delivered on Applied Physics Letters. (vol.95, issue 18, id.181901,2009) entitled
It is sharp in " Broadband planar Luneburg lens based on complementary metamaterials " paper
Devise the Luneberg lens antenna for working in Ku wave band with electromagnetism Meta Materials, but due to be using the pcb board of adhesion metal come
Realize Meta Materials, the loss for resulting in the antenna is excessive, and antenna aperture efficiency is very low.In the special of Publication No. CN107627611A
In benefit, a kind of spherical Luneburg lens design method based on 3D printing technique is disclosed, cost is four points of traditional batch structure
One of, the dielectric constant of each basic unit is adjustable, but the dielectric constant of at least one material is not more than 1, at least one material
The dielectric constant of material is not less than 2, is not available same material and is processed, and material of the dielectric constant no more than 1 is actually
It is difficult to realize.In the patent of Publication No. CN107369876A, the day knot of a kind of packaged lens and reflection floor is disclosed
Structure carries out beam scanning entirely through mechanical arm regulation lens relative position, and real-time is poor.Hao Yang in 2014 et al. is in IEEE
Entitled " the Flat Luneburg Lens via delivered on Transactions On Antennas and Propagation
In Transformation Optics for Directive Antenna Applications " paper using variation optics at
Function scans spherical Luneburg lens boil down to cylinder shape medium lens only interior to 34 °, and most by Mechanical Moving feed
Layer dielectric constant is up to 12, it is difficult to realize and actual processing is at high cost.
Compared with former invention disclosed patent and paper, lens antenna of the invention is saturating mainly for traditional spheroidal dragon uncle
Mirror body product is big, and outermost layer dielectric constant is lower not easy to be processed, and the problem that traditional phase-array scanning angle is small, gain is low, uses
Transform optics carries out compression to form section being elliptical layered medium lens antenna, compression ratio 2, drop to the primary lens of traditional ball dragon
Low section half, and every layer of dielectric constant is limited, after loading phased array feed, by element pattern principle of stacking,
Optimize phased array width phase using optimization algorithm, is emulated in commercial electromagnet simulation software Ansys HFSS, relative to feed
Phased array gain itself improves 7dBi, and scan angle spreads to 45 °, antenna aperture efficiency 51%.The configuration of the present invention is simple, dielectric are normal
1.5~3, processing can take same material to carry out 3D printing for number control, be suitable for millimeter wave frequency band, low cost, compared with low section
With the scenes such as large-angle scanning.
Summary of the invention
It is saturating to propose the large-angle scanning ellipsoid medium based on phased array feed in view of above-mentioned technical background and requirement by the present invention
Mirror antenna, specifically, for the ellipsoid di-lens for working in Ka frequency range, which passes through transform optics method for traditional ball
It is elliptical dielectric stratifying lens that the primary lens of shape dragon, which are compressed into section, which is always divided into 5 layers, and compression ratio 2 reduces section
Half.Phased array feed uses microband paste unit, coaxial feed, and cell spacing is 0.65 times of wavelength, totally 9 units, Jiao Jing
Than being only 0.1.It is emulated using commercial electromagnet simulation software Ansys HFSS, when phased array individually scans, 0 ° of gain is
16.7dBi, when scanning is to 45 °, gain 14.05dBi, and occur graing lobe since 40 °, scan performance sharp fall.
And the ellipsoid di-lens optimizes phased array width phase using element pattern superposition algorithm under phased array excitation, can be realized
± 45 ° of scannings, no graing lobe, and 24.2dBi (antenna aperture efficiency 51%) when gain is up to 0 °, when scanning is to 45 °, gain
For 20.68dBi.Compared to feed phased array itself, the ellipsoid dielectric lens antenna of phased array feed by transform optics and
Element pattern superposition algorithm realizes the significantly promotion of gain, averagely improves 7dBi, and beam scanning angular region expands
To 45 °, multi-beam beam system and large-angle scanning communication system can be preferably applied for.
Transform optics (TO) is a kind of about the distribution for changing electromagnetic parameter by coordinate transform, is thought to reach us
The electromagnetic nature to be realized.In the design process of the ellipsoid di-lens, present invention utilizes transform optics to come to tradition
Spherical Luneburg lens are compressed and keep certain antenna aperture efficiency (51%).
The core concept of transform optics is the invariance based on maxwell equation group equation group form under coordinate transform.
By this invariance, following formula can be obtained:
A is Jacobian matrix, is the transition matrix from luv space to transformation space, ATFor the transposition of A.
During designing ellipsoid di-lens, by above formula, the distribution of dielectric constant can be calculated, it will
Distribution substitutes into optimization algorithm, can optimize to remaining parameter, form final axis than the ellipsoid lens medium day for 2
Line.After the value range for limiting dielectric constant, can be avoided the primary lens outermost layer of traditional dragon cross low-k can not be equivalent
The problem of, while on short-axis direction, 2 times of compression is formd, the section for bringing lens antenna reduces, and can more answer
For low section scene.
The element pattern superposition algorithm that the present invention uses can simulate phased array in electromagnetic simulation software in real time and feed
The scanning situation of ellipsoid di-lens control to gain directly can be achieved different from the normalized radiation pattern simulated usually
System, and it is not limited to the control of pattern shapes.Specific formula is as follows:
Compared to traditional normalized radiation pattern algorithm, phased array is optimized using element pattern superposition algorithm of the invention
Width mutually can preferably control gain and large-angle scanning.
Detailed description of the invention
Fig. 1 is transform optics ellipsoid di-lens dielectric constant distribution map of the present invention;
Fig. 2 is the tomograph of the large-angle scanning ellipsoid dielectric lens antenna fed the present invention is based on phased array;
Fig. 3 is the side view of the large-angle scanning ellipsoid dielectric lens antenna fed the present invention is based on phased array;
Fig. 4 is scan pattern of the phased array independent drive of the present invention in 28GHz;
Fig. 5 is the standing wave of the large-angle scanning ellipsoid dielectric lens antenna that feeds the present invention is based on phased array in 27-29GHz
Than;
Fig. 6 is the large-angle scanning ellipsoid dielectric lens antenna that feeds the present invention is based on phased array in the scanning direction of 28GHz
Figure;
Specific embodiment
It is ellipse after Fig. 1 is illustratively described using optics is changed to the progress compressive deformation of traditional spheroidal Luneberg lens antenna
The dielectric constant distribution situation of ball di-lens, according to shown in figure, the center dielectric constant of ellipsoid di-lens is up to 4, on side
Edge outermost layer gradually approaches 1, it is possible thereby to carry out scope limitation to the dielectric constant of ellipsoid di-lens in optimization algorithm
1.5~3, both met the property of transform optics, and also can guarantee that dielectric constant will not be too low.Fig. 2 and Fig. 3 are described based on phased array
The design structure of the large-angle scanning ellipsoid dielectric lens antenna of feed, as shown in figure, this structure includes from outside to inside five layers ellipse
Ball medium (1) (2) (3) (4) (5), the rectangular microstrip patch antenna array of 1*9 (6) (7) (8).
Ellipsoid di-lens long axis and the axis of short axle ratio are 2 (section reduction half), and using long axis as diameter, and short axle is thickness
Degree reduces the thickness of the primary lens of traditional spheroidal dragon, by optimization algorithm, in the model of dielectric constant 1.5~3 on short-axis direction
It encloses under limitation, each layer of dielectric constant and size is optimized, form the ellipsoid dielectric lens antenna such as Fig. 2, this is thoroughly
Mirror maintains the characteristic of original primary lens of dragon, and the antenna aperture efficiency emulated in commercial electromagnet simulation software Ansys HFSS is
51%.Phased array is 0.65 times of wavelength apart from rims of the lens, and burnt diameter is than being only 0.1.What phased array element was taken is rectangular micro-strip
Patch (6), and coaxial feed is used, simple easy processing, the element pattern superposition algorithm proposed through the invention realizes wide angle
Scanning to 45 ° and gain averagely improve 7dBi.
Fig. 4, which is described, (is not loaded with ellipsoid di-lens) when only phased array feed, by distributing phase to phased array,
The 28GHz scan pattern (Surface scan where direction of structuring the formation) emulated in commercial electromagnet simulation software Ansys HFSS.
As shown in Figure 4, phased array starts graing lobe occur when scanning is neighbouring to 40 °, and scan performance largely declines at this time, is not enough to full
The application scenarios of foot breadth angle sweep.
Fig. 5 describes the ellipsoid di-lens based on phased array feed in the standing-wave ratio of 9 ports of 27-29GHz, by scheming
Shown in 5, in 27-29GHz frequency range, 9 port standing-wave ratios are respectively less than 2.25.
Fig. 6 describes the ellipsoid di-lens based on phased array feed in the scan pattern of 28GHz.First according to unit side
To figure superposition algorithm, optimization obtains the amplitude and phase of each unit, substitutes into commercial electromagnet simulation software AnsysHFSS, shape
At such as the scan pattern (Surface scan where direction of structuring the formation) of Fig. 5.As shown in Figure 5, at 0 ° (not scanning), ellipsoid medium is saturating
Mirror gain is 24.2dBi, and relative to feed phased array itself, gain improves 7.5dBi;When scanning is to 45 °, ellipsoid medium is saturating
Mirror gain is 20.68dBi, and relative to feed phased array itself, gain improves 6.6dBi, while visible graing lobe has disappeared,
Minor lobe is respectively less than -10dBi, hence it is evident that improves scanning angle, gain also has very big promotion.
It is the description to the present invention and its embodiment provided to the engineers and technicians in familiar field of the present invention above,
These descriptions should be considered to be illustrative and not restrictive.Engineers and technicians can be accordingly in invention claims
Thought is done specific operation and is implemented, and naturally also can do a series of change to embodiment according to the above.It is above-mentioned these all
It should be considered as coverage of the invention.This method can be that formation formula in face is expanded to two dimensional beam by changing feed phased array
Sweep situation.